Data From COVID-19 Pandemic Reveals High Rates of Asymptomatic RSV in Pregnancy

Asymptomatic respiratory syncytial virus (RSV) infection was more frequently identified among pregnant women between 2021 and 2023, likely due to changes in testing practices related to the COVID-19 pandemic. However, severe RSV outcomes were uncommon, indicating pregnancy is not a risk factor for severe disease. These findings were published in Open Forum Infectious Diseases.

Researchers conducted a cross-sectional study using data from the RSV Hospitalization Surveillance Network to compare characteristics and outcomes between pregnant and nonpregnant before the COVID-19 pandemic (2014-2018). They also compared outcomes among pregnant women with respiratory symptoms before vs during the pandemic (2021-2023), as well as among pregnant women with vs without respiratory symptoms in the pandemic period. Multivariable logistic regression was used to examine the relationship between pregnancy and severe RSV outcomes, including intensive care unit (ICU) admission and in-hospital mortality.

Data from a total of 11,309 adult RSV hospitalizations were captured for the analysis, of which 387 occurred among women in the pre-pandemic period and 655 occurred among women in the pandemic period. Of women (age range, 18-49 years) hospitalized during these periods, 41 (10.6%) and 238 (36.7%) were pregnant at admission, respectively.

Most women (90.4%) hospitalized during the pre-pandemic period experienced at least 1 acute respiratory infection symptom, and 33 (9.4%) of these women were pregnant at admission.

Stratified by pregnancy status, nonpregnant women with RSV symptoms were older (median age, 37.6 vs 31.6 years; P =.005), had longer hospital stays (median, 3.6 vs 2.4 days; P =.006), and were more likely to require ICU admission (23.4% vs 15.2%). Nonpregnant women also had higher rates of shortness of breath (70.3% vs 42.4%; P =.001), nonacute respiratory infection symptoms (67.8% vs 48.5%; P =.026), and underlying medical conditions (87.4% vs 42.4%; P <.001), including cardiovascular disease, chronic lung disease, diabetes, immunosuppressive conditions, and neurologic disorders.

Multivariable analysis demonstrated that pregnancy was not a risk factor for ICU admission or in-hospital mortality among women with RSV infection. However, the risk for severe outcomes was significantly increased for women with diabetes (adjusted risk ratio [aRR], 1.78; 95% CI, 1.16-2.74; P =.008) and for women with neurologic disorders (aRR, 1.57; 95% CI, 1.24-1.98; P <.001), regardless of pregnancy status.

Further analysis of pregnant women with RSV in the pre-pandemic and pandemic periods showed that 33 (80.5%) and 84 (35.3%) were symptomatic at admission, respectively. No significant between-group differences were noted in terms of median age, race/ethnicity, median length of hospital stay, or underlying conditions.

For pregnant women who were hospitalized with RSV during the pandemic period, 84 (35.3%) were symptomatic at or within 2 weeks prior to admission and 154 (64.7%) were asymptomatic. Although symptomatic pregnant women had higher rates of asthma (27.4% vs 15.6%; P =.029) and underlying conditions overall (41.7% vs 27.9%; P =.031), no significant between-group differences were observed in median length of hospital stay. Moreover, pregnancy and infant outcomes among asymptomatic vs symptomatic pregnant women who delivered during their RSV admission (84.4% vs 54.9%; P <.001) were not significantly different.

Limitations of this study include the use of data based on clinically-driven testing practices, changes in testing practices over time, insufficient data on pregnancy complications, the inability to discern whether patients were admitted for labor and delivery or for other reasons, and the lack of data on infant outcomes for those who were delivered following hospital discharge.

“Although the direct maternal benefit of maternal RSV vaccination may be low in preventing RSV-related hospitalization in pregnant women, RSV vaccination of pregnant women could play an important role in preventing severe RSV disease in infants through maternal antibody transfer,” the researchers concluded.

Disclosures: Multiple study authors declared affiliations with pharmaceutical, biotech, and/or device companies. Please see the original reference for a full list of disclosures.

This article originally appeared on Infectious Disease Advisor